Clarity characteristics

Internal or external feature of a diamond that helps determine the quality and establish its identity.

Color grading

A system of grading diamonds based on either being colorless for white diamonds or hue, depth of color, and saturation of color for fancy color diamonds. For white diamonds, GIA uses a scale of D-Z in which D is colorless and Z is light yellow. Z should not be confused with yellow fancy color diamonds.

Crown

The upper portion of the diamond above the girdle. The crown contains a table facet and depending on diamond shape either star and bezel facets (round brilliant, oval, pear, radiant, princess, heart) or rows of concentric facets reaching from the table to the girdle (emerald, asscher).

Crown angle

The angle formed by the bezel facets and the girdle plane.

Crown height percentage

The distance from the girdle plane to the table expressed as a percentage of average girdle diameter.

Culet

A facet sometimes added to the bottom of the pavilion to protect the tip.

Cut

The proportions and finish of a polished diamond. Many Gemologists believe cut is the most important of the 4 Cs.

Cutting style

The arrangement of a diamond's facets.

Depth

The height of a diamond from the culet to the table and is measured in millimeters.

Depth Percentage

A ratio of the total depth of a diamond from table to culet compared to the total diameter.

Diamond

A crystal made up of 99.5% pure carbon atoms arranged in an isometric, or cubic, crystal arrangement.

Dispersion

When white light passes through the diamond and is broken up into spectral colors.

Eye clean

A term used to describe a diamond with no blemishes or inclusions that can be seen with the unaided eye.

Face-up (aka table up)

A position where the diamond's crown and table are pointed towards the viewer.

Face-down (aka table down)

A position where the diamond's pavilion is pointed towards the viewer.

Facet

A smooth flat plane on the surface of a diamond. Facets allow light to enter a diamond and reflect off its surface at different angles creating color and light.

Fancy cut

Any diamond shape other than a round.

Feather

A term for any break in a diamond.

Finish

A term used to describe the quality of the polish and symmetry of the cut in a fashioned diamond.

Fire

The flashes of colors in a polished diamond.

Fluorescence

The emission of visible light by a diamond when it is exposed to ultraviolet radiation.

French tips

A cutting style that replaces the large bezel facets at the points of a marquise, pear, and heart with star and upper girdle facets.

Girdle

The outer edge or outline of the diamond's shape.

Girdle thickness percentage

Girdle thickness expressed as a percentage of the average girdle diameter.

Inclusion

A clarity characteristic totally enclosed in a polished diamond or extending into it from the surface.

Length to Width ratio

A numerical expression between the length of a diamond and the width of a diamond where the value for width is one.

Lower girdle facet percentage

The length of the lower girdle facets expressed as a percentage of the total distance between the girdle and the culet.